Pipe machining apparatus

ABSTRACT

A pipe machining apparatus having a tool carrier rotatable about a frame mounted externally of a pipe, with the frame being formed of two semiannular sections which are releasably held together by connection devices including coacting pin and latch structures which are effectively positioned by means operable from the side of the frame. The tool carrier mounts at least one tool head having a tool slide for a tool movable radially of the pipe. The tool slide is movable by rotation of a feed screw which is rotated in a tool slide advancing direction by a rack and pinion structure including a rack adjustably mounted on a feed plunger which coacts with a tool advance cam on the frame. The rack is also mounted for pivotal movement to permit manual rotation of the feed screw in a tool slide retracting direction, which pivoting results from cogging of the pinion gears relative to the rack gears. The rack is adjustably threaded on the feed plunger to vary the stroke of the rack and adjust the feed rate relative to rotation of the tool carrier without change of the tool-advance cam to one of different contour.

This is a division of application Ser. No. 918,293, filed Oct. 14, 1986,now U.S. Pat. No. 4,762,038.

BACKGROUND OF THE INVENTION

This invention pertains to a pipe machining apparatus and, moreparticularly, to such apparatus that can be mounted externally of a pipeand which causes one or more tool heads to revolve about the pipe with atool head having a tool slide which may be advanced toward the pipe toachieve a particular machining operation. An apparatus of this typerequires a frame which can be easily and quickly mounted to the pipe andmeans for advancing the tool slide as the tool head revolves around thepipe. The invention relates to improvements in such structures.

DESCRIPTION OF THE PRIOR ART

The prior art has many examples of pipe machining apparatus which can bemounted in association with a pipe and carry one or more tools forperforming machining operations, such as beveling and cut off. Oneexample of such an apparatus is shown in U.S. Pat. No. 4,543,861,wherein a tool head rotatable on a mandrel engageable within a pipesupports a tool for either cut off or beveling operation. The advance ofthe tool radially of the pipe is derived from intermittent engagementwith a tool advance cam carried on a stationary element and which isintermittently engaged by tool-advancing mechanism including linkagewhich is shifted to intermittently advance a feed screw associated witha tool slide by operation of the linkage transmitting motion through aone-way clutch. The tool-advancing mechanism is relatively complexbecause of the necessity for the linkage to be of variable lengthbecause of the adaptability of the machine for cutting at variousangles.

Additional prior art showing intermittently pulsed mechanism for causingtool advance includes the Gilmore U.S. Pat. No. 3,908,491 wherein thepulsing is derived from a stationary tool-advancing cam and Mayfield etal. U.S. Pat. No. 4,397,202 wherein a pawl and ratchet tool-advancingmechanism is pulsed by engagement with a tool-advancing cam.

The known prior art does not disclose a rack and pinion drive foradvancing a tool slide in response to intermittent engagement with atool advance cam, with adjustability of the rack to vary the amount ofadvancing movement of the tool slide and pivotal mounting of the rack tofreely permit manual retraction of the tool slide, nor does the priorart disclose the claimed pin and latch structure for associatingsemiannular sections of a frame attachable to a pipe for support of theapparatus externally of the pipe.

SUMMARY OF THE INVENTION

A primary feature of the invention is to provide a pipe machiningapparatus having new and improved structure for advancing a tool sliderelative to a pipe in response to intermittent engagement with a tooladvance cam, with ready adjustability of the feed movement of the toolslide, without substitution of a different tool advance cam.Additionally, the structure of the tool advancing mechanism permitsretraction of the tool slide without pre-release of engagement betweencomponents of the tool-advance mechanism.

Another feature of the invention is to provide new and improved lockingstructure for interconnecting a pair of semiannular sections which, whenjoined together, define a frame attachable to the exterior of the pipeand which rotatably mounts a tool carrier which supports one or moretool heads having tool slides for tools that may be used in performingcutting operations on the pipe.

In carrying out the foregoing, the pipe machining apparatus has a frameattachable to the exterior of a pipe and formed by a pair of semiannularsections in abutting relation and held together by novel pin and latchstructure operable from the side of the frame, a tool carrier rotatablymounted on the frame, with means on the frame for rotating the toolcarrier, one or more tool heads fixed to the tool carrier and having atool slide for movement radially of the pipe, a movable feed plunger onthe tool head and a tool-advance cam on the frame in the path of thefeed plunger, and a rack and pinion structure for converting motion ofthe feed plunger to movement of the tool slide, including apivotally-mounted rack on the tool head and a pinion operativelyconnected to a feed screw for the tool slide through a one-way clutch,with the rack being connected to the feed plunger and the rack and feedplunger being mounted for pivotal movement on a pivot block withyieldable means for holding the rack in engagement with the pinion,whereby engagement of the feed plunger with the tool advance cam exertsa force on the rack urging it into engagement with the pinion and alsocauses linear movement of the rack to rotate the pinion. Reverserotation of the pinion when retracting the tool slide causes cogging ofthe pinion relative to the rack, as permitted by the yieldable mountingof the rack.

Additionally, the rack is threaded onto the feed plunger and a feedadjustment nut is also threaded to the feed plunger, which acts to limitthe retracting movement of the feed plunger, after disengaging from thetool-advance cam and with the rack being adjustable lengthwise of thefeed plunger and held in adjusted position by the feed adjustment nut tocontrol the extent to which the feed plunger can retract and, thus,determine the amount of the advancing stroke thereof when the feedplunger next engages the tool-advance cam.

Further, the aforesaid latch and pin structure includes a pair ofrecesses in adjacent ends of the semiannular sections of the frame, withone of the recesses having a pin with an exposed part in the recess andthe other recess having a movable latch extending outwardly of therecess and normally urged to a retracted position. When the framesections are brought into abutting relation, the latch enters the recesshaving the pin and an externally-operable member can be advanced intoengagement with the latch to move the latch from retracted position intointerlocking relation with the pin.

An object of the invention is to provide a pipe machining apparatuscomprising, a tool carrier, means attachable to a pipe for rotatablymounting the tool carrier, means for rotating the tool carriercircumferentially about the pipe, a tool head mounted on the toolcarrier and having a tool slide for movement radially of the pipe, amovable feed plunger on said tool head, a tool advance cam on the meansattachable to the pipe and in the path of said feed plunger, means forconverting motion of the feed plunger to movement of the tool slideincluding a pivotally-mounted rack and a pinion, said rack beingconnected to said feed plunger, and yieldable means for holding the rackin engagement with the pinion and permitting rotation of the pinionrelative to the rack by forced movement of the rack away from thepinion.

Another object of the invention is to provide a pipe machining apparatushaving a rotatable tool carrier mounting a tool head with a movable toolslide, and means attachable to a pipe or the like for movably supportingthe tool carrier including two semiannular sections and means forsecuring said sections together in abutting relation with theimprovement therein comprising, a pair of connection devices operablefrom the side of the sections and having components at the end of eachsemiannular section, said connection devices each comprising a recess atthe adjacent ends of the semiannular section, a pin positioned in onerecess with an exposed part, a pivoted latch member positioned in asecond recess and extending outwardly therefrom, yieldable means urgingthe latch member to a retracted position to enable insertion of thelatch member into the recess having the pin, and a movable memberexposed to the side of the semiannular section and extending into therecess having the pin for engagement with the latch member wherebyadvance of the movable member pivots the latch member into lockingengagement with the exposed part of said pin.

Still another object of the invention is to provide a pipe machiningapparatus having a frame attachable to a pipe or the like, a toolcarrier rotatably mounted on said frame, at least one tool head fixed tosaid tool carrier, a tool slide mounted on said tool head for movementradially of the pipe, the improvement in means for advancing the toolslide while enabling manual retraction thereof comprising, a feed screwthreaded into the tool slide, a pinion drivingly associated with thefeed screw in one direction of rotation through a one-way clutch, apivot block pivoted on said tool head, a feed plunger reciprocable insaid pivot block and having a threaded section, a rack threaded onto thethreaded section of the feed plunger and in mesh with said pinion, atool advance cam on the frame positioned to engage the feed plunger asthe tool carrier rotates to cause an advancing stroke of the feedplunger, yieldable means urging the feed plunger to move in a retractingstroke, a feed adjustment nut threaded on the threaded section of thefeed plunger in abutting relation with the rack to prevent rotation ofthe rack on said threaded section and to engage the pivot block andlimit the retracting stroke of the feed plunger, and yieldable means tourge the rack into mesh with the pinion, and the pivot mounting of thepivot block to the tool carrier being located whereby a force exerted bythe tool advance cam on the feed plunger urges the rack toward thepinion.

cl BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view of the pipe machining apparatus, shown inassociation with a pipe;

FIG. 2 is a fragmentary plan view of the pipe machining apparatus;

FIG. 3 is a front elevational view of the pipe machining apparatus;

FIG. 4 is a plan view of a tool head, with parts broken away;

FIG. 5 is a sectional view, taken generally along the line 5--5 in FIG.4;

FIG. 6 is a fragmentary perspective view, with parts broken away,showing a connection device for the frame of the apparatus; and

FIG. 7 is an exploded perspective view of the structure shown in FIG. 6.

DESCRIPTION OF THE PREFERRED EMBODIMENT

The pipe machining apparatus is shown generally in FIGS. 1, 2 and 3 inassociation with a pipe P. The pipe machining apparatus has a frame,indicated generally at 10, and formed of two joined-together semiannularsections 12 and 14 and which rotatably mount a tool carrier, indicatedgenerally at 20, composed of two semiannular sections 22 and 24.

The frame 10 carries three radially adjustable members 25, 26 and 27which can be brought into engagement with the exterior of the pipe P andsuitably adjusted in a known manner to locate the frame 10concentrically with the pipe. This assembly step is performed throughaccess holes in the tool carrier 20.

The tool frame 10 has a column 30 extending outwardly of the frame tohave a part thereof radially outward of the tool carrier 20 and whichmounts a suitable drive motor 32, such as an air motor with suitablegear reduction means, which drives a gear 34 meshing with a circulargear 36 on the outer periphery of the tool carrier 20. The tool carrier20 is movably mounted on the tool frame 10 by a dovetail guide structureand by rollers (not shown) mounted on the exterior of the tool frameengaging with grooves on the interior of the tool carriage 20, wherebyenergization of the motor 32 results in rotation of the tool carrier 20relative to the frame 10 by the driving engagement between the gears 34and 36.

The structure of the tool frame 10 and tool carrier 20 is moreparticularly shown in FIGS. 6 and 7. Each of the tool frame sections 12and 14 have components at the ends thereof defining a pair of connectiondevices. One of the connection devices is seen particularly in FIGS. 6and 7 and includes a pair of recesses 40 and 41 in the adjacent ends ofthe sections, with the recess 40 having a pin 42 with a part thereofexposed centrally of the recess 40 and the recess 41 having a latchmember 44 extending outwardly therefrom and mounted for pivotal movementon a pivot pin 45. Yieldable means in the form of a spring 47 engagesthe latch member 44 at a location relative to the pivot pin 45 to urgethe latch member 44 to a retracted position, as shown in FIG. 7. Whenthe ends of the frame sections 12 and 14 are brought into abuttingrelation and into alignment by pins 48 engaging in holes 49, the latchmember 44 is pivoted from its retracted position to the position shownin FIG. 6 to interlock with the pin 42. This interlocking relation isachieved by advancing movement of a member carried on the frame section12 into engagement with the latch member 44 to cause pivoting thereof.This advancing member is shown in the form of an externally-threadedmember 50 operable from the side of the frame 10. When the frame is tobe disassembled, the threaded member 50 is backed-out and the spring 47is operable to pivot the latch member 44 to its retracted position outof engagement with the pin 42.

The tool carrier 20 has coacting plugs and holes at opposite ends of thetool carrier sections 22 and 24 to bring the sections into alignmentwhen the tool carrier is assembled, with the section 22 having the plugs52 and the section 24 having openings 53 to receive the plugs. Anexternally-operable threaded member can be advanced through an opening54 in the section 24 into threaded engagement with an opening 55 in thesection 22 to hold the carrier sections together. The structure shown inFIGS. 6 and 7 is duplicated at the opposite ends of both the framesections 12 and 14 and the tool carrier sections 22 and 24. In order toretain the tool carrier sections 22 and 24 in loose pivotal relation, afloating hinge connection is provided at 58 at both the front and rearof the tool carrier.

The tool carrier 20 can mount one or more tool heads, with two toolheads 60 and 62 being shown in FIGS. 1 to 3. These tool heads aresuitably attached to the tool carrier, whereby rotation of the toolcarrier causes the tool heads to revolve around the pipe P. Each of thetool heads movably mounts a tool slide, with the respective tool slidesbeing shown at 64 and 66 and carrying the respective tools 68 and 70. Asan example, one of these tools can be a bevel tool and the other aparting tool for cut-off.

Each of the tool heads may be of the same construction and the tool head60 is shown in FIGS. 4 and 5. The tool head 60 has a plate 75 formedwith a recess which mounts a bushing 76 which rotatably receives a feedscrew 77 having a threaded section threadably engaged with the toolslide 64 and a section 78 rotatable in the bushing 76. The section 78mounts a surrounding pinion 80 which is rotatably associated with thefeed screw by a one-way clutch bearing 82. This one-way clutch bearingcan be a type DC roller clutch offered by Torrington. The one-way clutchbearing results in rotation of the feed screw when the pinion rotates inone direction, and nonrotation of the feed screw when the pinion rotatesin the other direction. The one-way clutch bearing 82 and pinion 80 areheld in position between a pair of thrust bearings 84 and 86 by a washer88 compressively engaged by a nut 89 on a threaded end 90 of the feedscrew 77 and with the reaction to the compressive engagement beingthrough a flange 91 on the feed screw. A roll pin 92 engages within apair of notches at the upper end of the nut 89 and extends through thethreaded end 90 of the feed screw to lock the nut to the feed screw fora purpose to be described.

The feed screw 77 is caused to rotate through rotation of the pinion 80by coaction of a movable feed plunger 100 having a rack 101 meshing withthe pinion 80 and which coacts with a tool advance cam 102 on the column30.

The movable feed plunger 100 has a dome-shaped end 105 for engagementwith the tool advance cam 102 as the tool carrier 20 rotates about thepipe in the direction of the arrows shown in FIG. 3. The feed plunger isurged outwardly toward the tool advance cam by a surrounding spring 106,with the feed plunger being shown in extended position in FIG. 4, ascaused by engagement with the tool advance cam. This engagement isintermittent and occurs once each time on each revolution of the toolcarrier 20 and, as the feed plunger advances from the retracted positionto the advance position shown in FIG. 4, the rack 101 causes rotation ofthe pinion 80 which, through the one-way clutch bearing 82, causesrotation of feed screw 77 and resulting advance of the tool slide 64.The rack 101 has an internally-threaded bore 110 which threadably mountsthe rack 101 to a threaded section 111 of the feed plunger. With thisconstruction, it is possible to adjust the rack 101 lengthwise of thefeed plunger and control the length of the advancing stroke of the feedplunger. A feed adjustment nut 115 is also threaded onto the threadedsection 111 of the feed plunger and is used to hold the rack 101 inadjusted position and also abuts against an end of a pivot block 120when the feed plunger is in retracted position. With the rack beingadjustable lengthwise of the feed plunger and the feed adjustment nut115 being positioned in abutment with the rack after adjustment, it willbe seen that the location of the rack and the feed adjustment nutdetermines the extent to which the feed plunger can retract and, thus,the extent to which the tool-advance cam 102 will be effective to movethe feed plunger in an advancing direction. If the feed plunger cannotretract to a position to engage the full length of the tool-advance cam102, it engages only a portion of the cam surface and, thus, there is alesser advancing stroke.

The feed plunger is mounted in the pivot block 120 by means of a bushing125, with the pivot block being mounted on the tool head 60 by a pivotmounting 126. The pivot block is provided in order to enable simplemanual retraction of the tool slide 64.

With the tool carrier 20 rotating clockwise, as viewed in FIG. 3 and asindicated by the arrows in the Figure, it will be seen that thedome-shaped end 105 of the feed plunger engages the tool-advance cam 102after the pivot mounting 126 has moved past the tool-advance cam wherebythe force exerted by the tool-advance cam acts in a direction about thepivot mounting 126 to urge the rack 101 into firm mesh with the pinion80 as well as to advance the feed plunger and the rack. The one-wayclutch bearing 82 transmits this motion to the feed screw. When the toolslide is to be retracted, it is necessary to rotate the feed screw 77 inan opposite direction, and this is done by use of a tool engaging thenut 89 fixed to the threaded end 90 of the feed screw by the roll pin92. Rotation of the feed screw 77 in a direction to retract the toolslide results in rotation of the pinion 80 through the one-way clutchbearing 82. However, movement of the rack 101 is prevented because ofengagement of the feed adjustment nut 115 with the pivot block 120. Inorder to permit movement of the pinion 80, the pivot block 120 can pivotclockwise and with the tapered shape of the gear teeth on the pinion 80and the rack 101, the rack is cammed outwardly by the teeth shape aspermitted by pivoting of the pivot block 120 and the pinion teeth "cog"along the rack teeth. This action is against yieldable means urging therack 101 into engagement with the pinion, with this yieldable meansincluding an outwardly-urged pin 130 movably mounted within a tube 131housing a spring 132 and with the tube being adjustably mounted in amember 135 carried by the plate 75. This yieldable means acts topreclude pivoting of the pivot block 120 in a clockwise direction as thefeed plunger 100 retracts in normal cutting operation but yields topermit the cogging action when the feed screw 77 is manually rotated ina direction to retract the tool slide. A cover member 140 for the plate75 is shown in broken line in FIG. 5.

With the adjustable rack and feed adjustment nut structure, it ispossible to vary the rate of advance of the tool slide relative to therate of rotation of the tool carrier without changing the shape of thetool advance cam 102. The tool advance cam is pivotally-mounted on thecolumn 30 by a pivot pin 140 and is urged outwardly by a spring (notshown). A retractable pin 141, carried by the column 30, can be movedinwardly to a position behind the tool-advance cam to hold it inoperative position, as seen in FIGS. 1 and 2. When it is desired to haverotation of the tool carrier without advance of a tool slide, the lockpin 141 can be raised to a position clear of the tool-advance camwhereby the tool advance cam is free to retract each time it iscontacted by the dome-shaped end 105 of the feed plunger.

I claim:
 1. A pipe machining apparatus having a rotatable tool carriermounting a tool head with a movable tool slide, and means attachable toa pipe or the like for movably supporting the tool carrier including twosemiannular sections and means for securing said sections together inabutting relation with the improvement therein comprising, a pair ofconnection devices operable from the side of the sections and havingcomponents at the end of each semiannular section, said connectiondevices each comprising a recess at the adjacent ends of the semiannularsections, a pin positioned in one recess with an exposed part, a pivotedlatch member positioned in a second recess and extending outwardlytherefrom, yieldable means urging the latch member to a retractedposition to enable insertion of the latch member into the recess havingthe pin, and a movable member exposed to the side of the semiannularsection having the recess with the pin and extending into the recesshaving the pin for engagement with the latch member whereby advance ofthe movable member pivots the latch member into locking engagement withthe exposed part of said pin.
 2. A pipe machining apparatus having arotatable tool carrier mounting a tool head with a movable tool slide, aframe for movably supporting the tool carrier including two semiannularsections and means for securing said sections together in abuttingrelation comprising, a connection device having components at the endsof adjacent semiannular sections, said connection device includingrecesses at the adjacent ends of the semiannular sections, a pinpositioned centrally in one recess with an exposed part, a movable latchmember positioned in a second recess and extending outwardly therefrom,yieldable means urging the latch member to a retracted position, and amovable member associated with said one recess and extending into saidone recess for engagement with the latch member whereby advance of themovable member moves the latch member into locking engagement with theexposed part of said pin.